Debate Grows on Aspirin for Heart Risk

May 28, 2009 -- Daily aspirin therapy is often recommended for otherwise healthy people who are at risk for heart attack or stroke, but a new analysis suggests that aspirin's risks may outweigh it benefits in this population.

There has been much debate, however, about whether aspirin should be routinely recommended for the primary prevention of cardiovascular events in people who do not have heart disease or a history of cardiovascular events, but who have risk factors for such events.

On the benefit side, aspirin therapy has been proven to lower the risk for both primary and secondary heart attacks and non-bleeding-related strokes. On the risk side, its use is also associated with rare but potentially life-threatening gastrointestinal bleeding and strokes caused by bleeding.

In people without established heart disease, aspirin is usually recommended for those most at risk for having a heart attack or stroke.

But the new analysis reveals that these patients also have high risk for bleeding events.

"We found that the very people who are at increased risk for coronary heart disease are also at increased risk for bleeds," University of Oxford epidemiologist Colin Baigent, FFPH, tells WebMD.

Weighing Risks and Benefits

Baigent and a team of researchers from the U.K. conducted the analysis, which appears in the May 30 issue of The Lancet.

It included six high-quality primary-prevention studies with a combined enrollment of 95,000 low-to-average-risk people and 16 secondary-prevention studies with a combined enrollment of 17,000 high-risk patients.

The analysis revealed that:

In both the low-to-average-risk and high-risk participants, aspirin therapy reduced the risk of nonfatal heart attacks by about a fifth, Baigent says.

Aspirin therapy did not significantly lower stroke risk in the patients with no history of heart attack or stroke.

Daily treatment with aspirin was associated with an increased risk for internal bleeding by a third in the primary prevention trials.

Aspirin therapy was found to prevent five nonfatal heart attacks for every 10,000 low-to-moderate-risk patients treated, while one extra bleeding-related stroke and three extra gastrointestinal bleeds occurred, Baigent says.

"On the basis of these findings, we don't believe that general guidelines advocating the routine use of aspirin in healthy people can be justified," he says.